较新版本的 GCC 引发无效转换错误

Question

    class FixedDataBlock: public DataBlockHeaderCommon<BlockSize>
    {
    // Construction
    public:
        FixedDataBlock(void* pool, SizeT const entrySize, SizeT const alignment)
            : base_t(eBlkFixData, pool)
        {
            this_t* dummy = reinterpret_cast<this_t*>(0);
            // offsets is a type of uint16_t
            OffsetT dataStartBlockOffset = reinterpret_cast<OffsetT>( &dummy->data[0] );

        }

    // Member variables
    private:
        int8_t      data[ BlockSize-sizeof(header_t) ];
    };

error: invalid type conversion: "int8_t={signed char} *" to "uint16_t={unsigned short}" for line

OffsetT dataStartBlockOffset = reinterpret_cast( &dummy->data[0] );

//dummy->data[0] is signed char* and dataStartBlockOffset is unsigned short

The above code is compiling fine on windows but it is failing only with the GCC.

Answer 1

Using offsetof micro fixed compilation error. OffsetT dataStartBlockOffset = (OffsetT)offsetof(FixedDataBlock, data);